Spinning Unit for the Production of a Yarn

ABSTRACT

The invention relates to a spinning unit of the air-jet spinning machine, which serves the purpose of producing a yarn ( 2 ) from a fiber composite ( 3 ), whereas the spinning unit ( 1 ) possesses a spinning nozzle ( 4 ) with a vortex chamber ( 6 ) featuring an inlet opening ( 5 ) for the fiber composite ( 3 ), whereas the spinning unit ( 1 ) features air jets ( 21 ) directed into the vortex chamber ( 6 ), which flow into the vortex chamber ( 6 ) in the area of a wall ( 7 ) surrounding the vortex chamber ( 6 ) and through which air jets, during operation of the spinning unit ( 1 ), compressed air can be introduced into the vortex chamber ( 6 ) in a given direction of rotation, in order to confer upon the fiber composite ( 3 ) a rotation in the specified direction of rotation, and whereas the air jets ( 21 ) are connected to a source of compressed air ( 9 ) with the assistance of at least one fluid connection ( 8 ). In accordance with the invention, it is provided that the spinning unit ( 1 ) includes at least one replaceable throttle element ( 10 ), with the assistance of which the volume flow of the compressed air, which flows from the source of compressed air ( 9 ) into the vortex chamber ( 6 ) during the operation of the spinning unit ( 1 ), is limited, whereas the throttle element ( 10 ) is placed in the flow path of the compressed air between the source of compressed air ( 9 ) and the air jets ( 21 ).

This invention relates to a spinning unit of an air-jet spinningmachine, which serves the purpose of producing a yarn from a fibercomposite, whereas the spinning unit possesses a spinning nozzle with avortex chamber featuring an inlet opening for the fiber composite,whereas the spinning unit features air jets directed into the vortexchamber, which flow into the vortex chamber in the area of a wallsurrounding the vortex chamber and through which air jets compressed aircan be introduced into the vortex chamber in a given direction ofrotation, in order to confer upon the fiber composite a rotation in thespecified direction of rotation, and whereas the air jets are connectedto a source of compressed air with the assistance of at least one fluidconnection.

Spinning units conforming to this type are known in the state of theart, whereas the term “yarn” is generally understood to mean a fibercomposite, for which at least one part of the fibers is wound around aninner core. As such, this includes, for example, a yarn in theconventional sense, which may be processed into a fabric, for instancewith the assistance of a weaving machine. Likewise, the inventionrelates to air-jet spinning machines, with the assistance of whichso-called “roving” (another name: coarse roving) can be produced. Thistype of yarn is distinguished by the fact that, despite a certainstrength, which is sufficient for carrying the yarn to a subsequenttextile machine, it is still capable of being drafted. Thus, with theassistance of a drafting device, for example the drafting system of atextile machine processing the roving, for example a ring spinningmachine, the roving can be drafted, before it is finally spun.

However, regardless of the strength of the yarn, it is always desirablethat the air jets flowing into the vortex chamber are applied with adefined atmospheric pressure, since this has direct effects on the airflow within the vortex chamber and thus on the individual yarn parameter(strength, grip, etc.) and/or the yarn quality.

If the spinning pressure (=atmospheric pressure in the area of the airjets) is modified for the production of a new type of yarn, changing theatmospheric pressure of the source of compressed air supplying thespinning unit(s) with compressed air is known in the state of the art.Purely as a precautionary measure, it must be noted at this point that,with the framework of the invention, the term “source of compressed air”is understood to be that section of the air-jet spinning machine throughwhich the individual components/elements of the air-jet spinning machinerequiring compressed air (such as valves, compressed air cylinders, airjets of the spinning unit(s)) are supplied with compressed air. This maybe, for example, a pipe arrangement, which is connected to therespective components/elements on the one hand, and to a compressed airgenerator and/or the compressed air system of a spinning mill.

However, for such an approach, it is disadvantageous that acorresponding reduction in pressure in the area of the source ofcompressed air has effects not only on the spinning pressure, but alsoon the other components of the air-jet spinning machine requiringcompressed air. However, since such components are usually designed at adefined target pressure, malfunctions in such cases cannot be ruled out.

The task of this invention is to address this disadvantage and topropose a spinning machine with which, when needed, spinning pressuremay be reduced as much as possible without negative effects oncomponents located outside the spinning nozzle.

The task is solved by a spinning unit with the features of claim 1.

In accordance with the invention, the spinning unit is characterized bythe fact that it includes at least one replaceable throttle element. Theterm “throttle element” is understood to mean a component of thespinning unit that is placed in the flow path of the compressed airbetween the source of compressed air (such as in the form of acompressed air pipe) and the air jets specified above. Thereby, thethrottle element serves as a limit on the volume flow of compressed aftthat flows from the source of compressed air during the operation of thespinning unit, along its flow path into the vortex chamber. In otherwords, there is optional use of a throttle element that, at a definedatmospheric pressure of the source of compressed air, enables a certainair volume flow in the area of the air jets. This specific air volumeflow in turn results in a certain atmospheric pressure in the area afterthe throttle element (seen in the direction of flow of the compressedair), such that, at a given atmospheric pressure from the source ofcompressed air, depending on the selection of the corresponding throttleelement, the spinning pressure may be adjusted to a defined amount,which in turn is smaller than (or, at a maximum, equal to) theatmospheric pressure from the source of compressed air.

While the atmospheric pressure within the source of compressed air mayalways remain constant (this has positive effects on the manner ofoperation of the components requiring atmospheric pressure, which areplaced outside the spinning nozzle), the spinning pressure is, dependingon the selection of throttle element, adjustable to a desired value(preferably to a value between 3 and 6 bar).

In particular, it is advantageous if the throttle element is part of thefluid connection. Thus, it is conceivable to integrate the throttleelement directly into the fluid connection, which runs between thespinning nozzle and the source of compressed air or a correspondingconnection area of the same. Thereby, the throttle element may in turnbe designed as a component detachably connected to the fluid connection,which is found in the flow path dictated by the fluid connection orforms this together with the fluid connection. Thus, while the throttleelement can be placed as a separate component between two fluidconnections and can be replaced accordingly, it is also conceivable thatthe throttle element itself includes one or more fluid connections. Thethrottle element could include, for example, two compressed air tubesand one throttle section connecting the two compressed air tubes,whereas this in turn could be connected to the compressed air tubes in afixed or detachable manner. In this case, it would ultimately bepossible to replace not only the throttle section, but the entirethrottle element, which in this case would include the throttle sectionand one or more fluid connections, in order to limit the volume flow ofthe compressed air at the corresponding spinning unit to a given value.

It is advantageous if the throttle element features a minimum innercross-sectional area that is smaller than the minimum innercross-sectional area of the fluid connection. This eventually causes thecompressed air volume flow to be throttled in respect of one design, forwhich no throttle element would be available. Therefore, the spinningpressure can be determined through the selection of the minimal innercross-sectional area and/or of the corresponding throttle element.

It is also advantageous if the fluid connection is designed in tubularform. The tube preferably runs from a connection section of the spinningnozzle to a connection section of the source of compressed air spacedfrom this, whereas additional components (such as in the form of valves)may naturally be present between the connection section last mentionedand the source of compressed air, with which the individual spinningunits may be moved from an idle mode (in which no compressed air streamsthrough the air jets) into an operational state (in which the productionof yarn is carried out).

It is also advantageous if the fluid connection features at least twoseparate tube sections, and the throttle element is placed between therespective tube sections. Thus, it can be advantageous if the fluidconnection features a first tube section, which connects the spinningnozzle to the throttle element, and a second tube section, whichconnects the throttle element to the source of compressed air. Thethrottle element is preferably connected to the two tube sections in adetachable manner, and, depending on the yarn to be produced, may bereplaced quickly and preferably without tools.

It is likewise advantageous if the throttle element is formed in onepiece. For example, the use of a corresponding injection-moldingcomponent, which must be plugged solely between the correspondingconnection sections of the fluid connection, or correspondingly placedin another manner, is conceivable.

It is also expressly advantageous if the throttle element is made ofplastic. Particularly since, for each spinning unit, a multiple numberof throttle elements must be deposited with different throttlecharacteristics, in order to be able to adjust all spinning unitstogether for a new type of yarn, it is advantageous if the costs of thethrottle elements that are used are kept within certain limits.

It is also advantageous if the throttle element is connected to thefluid connection, the spinning unit and/or the source of compressed airwith the assistance of one or more plug connection(s) and/or screwconnection(s). Such connections are quick, and are usually able to bemade or detached without tools, such that, when necessary, the rapidreplacement of the respective throttle elements may be carried out.

It is also advantageous if the throttle element features at least oneconnection section, with which it is connected to the fluid connection,the spinning unit or the source of compressed air in a positive-lockingor frictional-locking manner. In the ideal case, the connection iscarried out without additional fastening elements, such that theintegration of the throttle elements or its connection sections is ableto be realized simply and cost-effectively. The respective connectionmay be carried out, for example, with the assistance of correspondinglatches or clip connections.

It is advantageous if the connection section features an uneven outercontour, through which it is connected to the fluid connection, thespinning unit and/or the source of compressed air. For example, theconnection section(s) could feature ring-shaped elevations andconstrictions, such that a tube section of the fluid connection slidingon the respective connection section is able to be securely connected tothe throttle element.

It also advantageous if the throttle element is connected to the fluidconnection, the spinning unit and/or the source of compressed air by oneor more quick coupler(s). Corresponding connection elements aregenerally known in the state of the art, and enable a rapid productionor release, as the case may be, of the connection of the specifiedcomponents, without tools. Thereby, it is typical that a spring orlocking mechanism is provided, which, after the connection of theindividual components to the quick coupler, prevents the respectivecomponents from being inadvertently disconnected. If a desiredseparation is carried out, for example, because the relevant throttleelement is to be replaced with a throttle element with a differentminimum inner cross-section, only the specified spring or lockingmechanism must be operated to bring about a release of the correspondinglocking/fixing.

It is also advantageous if the spinning unit possesses multiple throttleelements connected in series or parallel, which are placed in the flowpath of the compressed air between the source of compressed air and theair jets. In this manner, it is possible to realize a variety ofspinning pressures with a small number of base throttle elements. Forexample, a throttle, which, at an atmospheric pressure from the sourceof compressed air of 6 bar, would bring about a spinning pressure of 3bar, could be connected in parallel to a throttle, which, upon anequivalent atmospheric pressure from the source of compressed air, wouldbring about a spinning pressure of 5 bar. In such a case, a spinningpressure of approximately 4 bar would ultimately be obtained.

Finally, it can be advantageous that the throttle element(s) is/aremarked by color or by corresponding shape. The marking could correspond,for example, to the volume flow of the compressed air, which passes bythe throttle element at a certain atmospheric pressure applied to therespective throttle element. In addition to the marking of the throttleelement, it could be equally advantageous to mark (by color) the tubesections connected to the throttle element.

Additional advantages of the invention are described in the followingembodiments. The following is shown:

FIG. 1 a partially cut side view of a spinning unit in accordance withthe invention,

FIG. 2 a cut-out of the section essential to the invention of a spinningunit in accordance with the invention,

FIG. 3 an alternative design of the section shown in FIG. 2, and

FIG. 4 a throttle element in accordance with the invention.

In FIG. 1, a partially cut side view of the spinning unit 1 of theair-jet spinning machine is shown, as it is already known in the stateof the art. The spinning unit 1 comprises a spinning nozzle 4 with aninlet opening 5, through which the fiber composite 3 to be spun (mostlyin the form of a drafted fiber composite) arrives in the so-called“vortex chamber” 6 of the spinning unit 1, in which the actual spinningprocess in turn takes place. The drafting is usually performed in adrafting system upstream to the spinning unit 1 (not shown in thefigures), from which the drafted fiber composite 3 is drawn, for examplewith the assistance of a pair of draw-off rollers. Finally, the fibercomposite 3 is preferably captured by a pair of delivery rollers,whereas its delivery rollers 19 are to be placed as much as possible inthe immediate vicinity of the inlet opening 5, in order to ensure thatthe fiber composite 3 may be delivered, reliably and evenly, from thedrafting system to the spinning nozzle 4.

After the fiber composite 3 has passed the inlet opening 5 of thespinning nozzle 4, it arrives in the effective area of several air jets21, as a rule flowing through a corresponding wall 7 tangentially intothe vortex chamber 6, which may be connected with each other, forexample, with the assistance of a ring channel 17, shown in FIG. 1. If,during the spinning operation, the ring channel 17 and the air jets 21branching off from it are subject to an excess pressure, this gives riseto a vortex air flow, which flows around the upper area of a yarnformation element 18 protruding into the vortex chamber 6. If theoutwardly protruding fiber ends of the fiber composite 3 arriving in thevortex chamber 6 are captured by this air flow, this gives rise to thedesired rotation of the fiber material in the area of the yarn formationelement 18 and, as a result, the desired yarn 2, which ultimately may bedrawn through a draw-off channel 22 from the vortex chamber 6.

In general, it should be clarified at this point that the produced yarn2 generally concerns an arbitrary fiber composite 3, which ischaracterized by the fact that an external part of the fibers (so-called“wrapped fibers”) is wrapped around an inner, preferably untwisted partof the fibers, in order to impart a certain strength on the yarn 2. Inaddition to conventional air-jet spinning machines, with the assistanceof which a yarn 2 in the conventional sense (which can be processed intoa fabric with the assistance of, for example, a weaving machine) can beproduced, the invention also includes an air-jet spinning machine, withthe assistance of which so-called “roving” can be produced. Rovingconcerns a yarn 2 with a relatively low share of wrapped fibers, or ayarn 2, for which the wrapped fibers are looped relatively looselyaround the inner core, such that the yarn 2 remains capable of beingdrafted. This is crucial if the produced yarn 2 should be or must bedrafted on a subsequent textile machine (for example, a ring spinningmachine), once again with the assistance of a drafting system, in orderto further process it accordingly.

Regardless of the type of yarn 2 to be produced (conventional yarn orroving), it is common with all air-jet spinning machines that thespinning unit(s) 1 is/are connected to a source of compressed air 9 by afluid connection 8, through which the air jets 21 may ultimately besupplied with the necessary compressed air (whereas the spinning nozzle4 itself may feature a preferably internal air line 20, with theassistance of which in turn there is a connection of the specified ringchannel 17 and fluid connection 8 connecting the spinning nozzle 4 withthe source of compressed air 9).

In FIG. 1, as an example, a pipe is shown as the source of compressedair 9, in which a corresponding excess pressure predominates (which, forexample, is connected with the assistance of a compressed air generatorfor the air-jet spinning machine, or to the compressed air supply of aspinning mill). However, as a general rule, within the framework of theinvention, the term “source of compressed air” is understood to be the(however developed) area of the air-jet spinning machine that (at leastduring yarn production) is subject to a certain excess pressure and isconnected to the spinning unit 1 through a corresponding fluidconnection 8, such that air from the source of compressed air 9 may flowinto the spinning nozzle 4.

Naturally, there may also be valves or other control devices between theair jets 21 and the source of compressed air 9, through which thespinning unit 1 is able to be brought from an idle mode (in which no airflows through the air jets 21) into a production mode, in which airstreams into the vortex chamber 6, in order to produce the desired yarn2.

Regardless of the exact form of the source of compressed air 9 and/orthe fluid connection 8, it is typical in the state of the art that thesource of compressed air 9 is connected not only with the spinningnozzle(s) 4, but also to other compressed air-operated elements, such asvalves or compressed air cylinders. The specified elements are usuallydesigned at a standard spinning pressure of, for example, 6 bar, whichin turn is made available by the source of compressed air 9.

If the spinning pressure, i.e. the atmospheric pressure in the air jets21, is changed during the spinning process in order to correspondinglyinfluence certain yarn parameters (strength, grip, etc.), this hasmostly negative effects on the manner of operation of the remainingcompressed air-operated elements, such as the valves or compressed aircylinders specified above, since, after the central adjustment of theatmospheric pressure made available by the source of compressed air 9,they are subject to pressure deviating from the standard atmosphericpressure.

In other words, in the state of the art, the spinning pressure may bechanged only by the central adjustment of the atmospheric pressure madeavailable by the source of compressed air 9, whereas this notinfrequently has negative effects on other elements of the air-jetspinning machine.

In order to counter this disadvantage, in accordance with the invention,it is now proposed that the spinning unit 1 is to be equipped with atleast one throttle element 10, with the assistance of which the volumeflow of the compressed air, which passes by the fluid connection 8during the operation of the spinning unit 1, is limited. On the basis ofthis limitation on volume flow, there is a reduction in atmosphericpressure, such that the atmospheric pressure, which is ultimatelyapplied to the air jets 21, is smaller than the atmospheric pressuremade available by the source of compressed air 9. Thus, depending on thethrottle element 10 used, the spinning pressure may be reduced to agreater or lesser degree in respect of the atmospheric pressure of thesource of compressed air 9. This ultimately has the crucial advantagethat the atmospheric pressure that is made available by the source ofcompressed air 9 cannot be maintained, such that the respectiveacceptors (valves, compressed air cylinders, etc.) of the air-jetspinning machine are always subject to a constant atmospheric pressure.By doing so, failures due to atmospheric pressure that is too low mayeasily be avoided.

By contrast, through a suitable selection of the throttle element 10,the spinning pressure applied to the air jets 21 may be adjusted to anarbitrary pressure between (theoretically) 0 bar and the (maximum)pressure made available by the source of compressed air 9. As a result,with a constant pressure from the source of compressed air, theproduction of different yarns 2 is possible, whereas only onecorresponding throttle element 10 must be used for this, or the throttleelement 10 currently used must be replaced with a throttle element 10with a modified flow cross-section.

As shown by example in FIGS. 2 to 4, there are now various options forarranging or placing the throttle element 10 in accordance with theinvention, which may be formed (for example) as a one-piece plasticelement, and is to feature a minimum flow cross-section that is smallerthan the minimum flow cross-section of the fluid connection 8, in orderto enable the desired reduction of the spinning pressure (if there is adesire for a spinning pressure that is equivalent to the atmosphericpressure made available by the source of compressed air 9, a throttleelement 10 may naturally also be used, the minimum flow cross-section ofwhich is larger than to or equal to the minimum flow cross-section ofthe fluid connection 8).

In any event, the throttle element 10 may be connected directly to thespinning nozzle 4 (FIG. 3) or to the source of compressed air 9, or asshown in FIG. 2, integrated into the fluid connection 8, whereas thismay be designed, for example, in tubular form, and preferably features afirst tube section 11 and a second tube section 12, which in turn areconnected to the throttle element 10. In the most simple case, it isultimately conceivable to integrate the throttle element 10 directlyinto the fluid connection 8, such that the spinning pressure could bechanged by replacing the entire fluid connection 8.

However, it is preferable that the throttle element 10 is formed as acomponent detachable from the fluid connection 8, whereas the connectionbetween the fluid connection 8 and the throttle element 10 (or betweenthe throttle element 10 and the source of compressed air 9 or thethrottle element 10 and the spinning nozzle 4) preferably should beformed in such a manner that a release of the same is possible withoutthe use of a tool.

For example, it is conceivable that the throttle element 10 (which maybe formed, for example, as a hollow body provided with two connectionsections 14) is connected to the neighboring sections (fluid connection8, spinning unit 1 or source of compressed air 9) of the spinning unit 1by a plug connection 13. FIGS. 2 and 4 show a particularly simplearrangement of such a plug connection 13. Thus, the throttle element 10may feature connection sections 14, which may be overlapped by the fluidconnection 8 designed, for example, in tubular form. For a particularlyreliable hold, it would also be worth considering to provide theconnection sections 14 with an uneven outer contour 15 shown in FIG. 4,such that the accidental removal of the fluid connection 8 or itsindividual sections (such as in the form of the first tube section 11 orthe second tube section 12) can be nearly ruled out.

In a further design of the invention, it is ultimately also conceivableto connect the throttle element 10 to the fluid connection 8, thespinning unit 1 or the source of compressed air 9 with the assistance ofone or more quick couplers 16. Such (usually spring-secured) quickcouplers 16 are generally known in the state of the art, and enable aparticularly easy, rapid and above all tool-free release of theconnection between the throttle element 10 and the components of thespinning unit 1 connected to it.

As a result, this invention thus proposes an air-jet spinning machinecomprising a spinning unit 1 or several spinning units 1, for which,depending on the desired yarn characteristics and through the selectionof the suitable throttle element 10, a defined spinning pressure isadjustable, whereas the atmospheric pressure made available by thesource of compressed air 9 must not be changed.

This invention is not limited to the illustrated and describedembodiments. Variations within the framework of the patent claims, suchas a combination of features, are also possible, even if they arepictured and described in different embodiments.

LIST OF REFERENCE SIGNS

-   1 Spinning unit-   2 Yarn-   3 Fiber composite-   4 Spinning nozzle-   5 Inlet opening-   6 Vortex chamber-   7 Wall-   8 Fluid connection-   9 Source of compressed air-   10 Throttle element-   11 First tube section-   12 Second tube section-   13 Plug connection-   14 Connection section-   15 Outer contour-   16 Quick coupler-   17 Ring channel-   18 Yarn formation element-   19 Delivery roller-   20 Air line-   21 Air jet-   22 Draw-off channel

1. Spinning unit of an air-jet spinning machine, which serves thepurpose of producing a yarn (2) from a fiber composite (3), whereas thespinning unit (1) possesses a spinning nozzle (4) with a vortex chamber(6) featuring an inlet opening (5) for the fiber composite (3), whereasthe spinning unit (1) features air jets (21) directed into the vortexchamber (6), which air jets flow into the vortex chamber (6) in the areaof a wall (7) surrounding the vortex chamber (6) and through which airjets, during operation of the spinning unit (1), compressed air can beintroduced into the vortex chamber (6) in a given direction of rotation,in order to confer upon the fiber composite (3) a rotation in thespecified direction of rotation, and whereas the air jets (21) areconnected to a source of compressed air (9) with the assistance of atleast one fluid connection (8), characterized in that the spinning unit(1) includes at least one replaceable throttle element (10), with theassistance of which the volume flow of the compressed air, which flowsfrom the source of compressed air (9) into the vortex chamber (6) duringthe operation of the spinning unit (1), is limited, whereas the throttleelement (10) is placed in the flow path of the compressed air betweenthe source of compressed air (9) and the air jets (21). 2-12. (canceled)